Previously in the art of processing lenses for eyeglass spectacles and the like, apparatuses for processing a lens have been used to process an uncut lens to fit the shape of a lens frame of a spectacle frame. Various prior art apparatuses for processing a lens are known; although certain lens processing apparatuses having the so-called “function of automatic beveled processing” have been provided. When a regular lens is used as the uncut lens and processed using this type of lens processing apparatus with the automatic beveled processing feature, specific additional information is required to process the lens besides the conventional data required. Specifically, data describing the shape of the frame is necessary in addition to the conventional information required for processing the uncut lens. When all of this information is provided to the apparatus having the automatic beveled processing feature, the apparatus automatically calculates a locus of a bevel most suitable for the lens undergoing processing and the bevel is formed along this calculated locus.
On the other hand, when the uncut lens is a special lens, such as a high power minus lens, a high power plus lens, an EX lens or a lenticular lens, the prior art lens processing apparatuses having the automatic beveled processing feature have certain drawbacks. Specifically, when processing a special lens using a prior art apparatus, the position of the apex of the bevel and the bevel curve, or the bevel ratio, must be manually set by an operator who watches a computerized simulation display. Therefore, adjustment of the position of the apex of the bevel and the bevel curve, or the bevel ratio, must be performed intentionally by the operator.
However, the manual setting of the locus of a bevel depends to a great degree on the skill and the experience of the operator. Therefore, it is difficult that the bevel is formed at a suitable position without a skilled operator.
In particular, it is difficult to achieve formation of the most suitable bevel having an excellent balance in these special lenses, such as the high power minus lens, the high power plus lens, the EX lens and the lenticular lens. Occasionally, as a result of manually setting the locus of the bevel, when the processing of the special lens is completed and the special lens is fitted into the intended lens frame, peripheral edges of the processed special lens protrudes unevenly from the rim, and the appearance of the entire spectacle glass is poor.
In recent years, the number of the skilled operators, who are able to accurately set the locus of the bevel while processing a special lens, is decreasing. Under these circumstances, there is a need for technology, which enables even persons not skilled in the art of lens processing to form a suitable bevel in the special lenses.
The present invention has, as an object, enabling persons not skilled in the art of lens processing to form a suitable bevel in special lenses using an improved apparatus having an automatic bevel processing feature.